A variety of designs have been commercialized or proposed for instruments which have an end effector for engaging tissue or other material during surgery and/or applying a fastener or other element to or through the material. Such instruments are typically actuatable from a handle, and some portions of the instrument may pivot and rotate to facilitate use of the instrument in various orientations. Examples of such instruments include tissue graspers, tissue clamps, needle graspers, tissue cutters, staplers, ligating clip appliers, and the like.
In many surgical procedures, the working area is confined, and instruments with relatively small cross sections are necessary or preferred. Thus, it would be desirable to provide improved assemblies that can be incorporated in a surgical instrument and that have relatively small cross sections.
In some surgical applications, it is necessary or advantageous to apply relatively high operating forces over particular portions of the instrument stroke length. Thus, it would be desirable to provide an improved actuator assembly that can provide a mechanical advantage for increasing the end effector force compared to the operator input force. It would also be beneficial if the actuator could accommodate designs wherein the operating force varies over the length of the stroke.
Additionally it would be advantageous to provide an improved assemblies that could be incorporated in instruments used in endoscopic surgical procedures as well as in instruments used in open surgery procedures. As used herein, the term "endoscopic" pertains generally to the use of a surgical instrument which is inserted into a body cavity in conjunction with an endoscope that is inserted into the same body cavity. The endoscope permits visual inspection, with or without magnification, of the interior of the body cavity and permits observation of the operation of the surgical instrument for therapeutic or diagnostic purposes.
In a typical endoscopic surgical procedure, the abdominal cavity of a human or animal subject is insufflated with a sterile gas, such as carbon dioxide, in order to provide increased maneuvering room within the body cavity for endoscopic instruments. Then, conventional trocars are inserted into the subject's body cavity through the surrounding skin, tissue, and musculature. A conventional trocar typically consists of a trocar cannula which houses an elongated trocar obturator. Trocar obturators typically have a piercing point, although other types of obturators are also available.
After each trocar has been positioned within the body cavity adjacent the target surgical site, the trocar obturator is removed leaving the trocar cannula as a pathway to the body cavity. A plurality of trocar cannulas are typically placed in this manner. The surgeon can then insert an endoscope through one of the trocar cannulas and can insert various types of endoscopic, surgical instruments through one or more of the other trocar cannulas at the target surgical site where the diagnostic or therapeutic surgical procedure is performed.
The endoscope is typically connected to a video camera, and the output from the video camera is fed to a video monitor which displays the surgical site and the end of the endoscopic instrument at the surgical site. Some endoscopic instruments incorporate a fastener-applying cartridge at the distal end which must be actuated. It would be desirable to provide an improved distal end assembly that can be employed in such endoscopic instruments and that can easily accommodate operation and control from the proximal end of the instrument exterior of the body cavity.
Although endoscopic surgical procedures offer many advantages, there are some problems associated with these procedures as conventionally practiced. For example, because the surgeon typically views the display on the video monitor as he manipulates instruments within the body cavity, the video display provides the surgeon with only a two-dimensional view of the surgical site, and there is a consequent loss of depth perception.
Another problem relates to engaging tissue from the instrument insertion direction. Some conventional, endoscopic instruments include an operable end effector (e.g., staple applying cartridge) for engaging the tissue in a certain way. In some of these conventional, endoscopic instruments, the end effectors are mounted to, and extend generally linearly with, a rigid, straight shaft of the instrument.
Depending upon the nature of the operation to be performed on the tissue within the body cavity, it may be desirable to provide an end effector assembly which can be easily rotated and/or angled or articulated relative to the longitudinal axis of the instrument shaft. This can permit the surgeon to more easily engage the tissue in some situations.
A further problem relates to the potential for blocking part of the field of view with the endoscopic instrument. Thus, the use of an endoscopic instrument with an articulating distal end would permit the surgeon to engage the tissue with an end effector laterally offset relative to the instrument's main shaft. This would permit the engaged tissue and instrument end effector to be better viewed through an adjacent endoscope with little or no interference from the main shaft.
Although a number of designs have been proposed for articulating endoscopic instruments, and although articulating endoscopes and other instruments are commercially available, it would be desirable to provide an improved design for a remotely operated end effector assembly that can accommodate articulation of the distal portion of the instrument.
In particular, it would be advantageous to provide an end effector assembly for an articulating instrument (endoscopic or non-endoscopic) with the capability for operation even when the assembly is oriented at a substantial oblique angle relative to the longitudinal axis of the instrument.
When an end effector is pivoted to an angled orientation relative to the longitudinal axis of the instrument, the mechanism for effecting the pivoting movement, depending upon the design of the mechanism, may require a greater applied force as the end effector approaches the maximum angle of divergence from the longitudinal axis. Accordingly, it would be advantageous to provide an improved system for pivoting an end effector with an increasing operating output force for an increasing pivot angle. Further, it would be beneficial if such an improved system could retain the desired angled orientation when the end effector is subjected to external forces and moments in the operating environment.
It would also be beneficial if such improved systems could be provided with sufficient strength to accommodate relatively high moments and forces during operation of the instrument in an articulated orientation as well as in a straight orientation.
It would also be advantageous if such improved systems for endoscopic or open surgery instruments could be provided with a relatively smooth exterior configuration having a minimum of indentations and projections that might serve as sites for contaminants and be hard to clean or that might be more likely to catch on, or tear, adjacent tissue.
Some instruments that are employed to apply fasteners are provided with a predetermined number of such fasteners. In some endoscopic instruments, such fasteners are stored in a cartridge at the distal end of the instrument. In some surgical procedures, it may be necessary to use more fasteners than can be stored in the instrument at one time. Accordingly, it would be desirable to provide an improved instrument for applying fasteners wherein additional fasteners can be added to the instrument. In particular, it would be advantageous if the empty fastener holder or cartridge could be removed and replaced with a new, full holder or cartridge.
Further, in order to minimize the likelihood that the cartridge could become inadvertently detached, it would be desirable to provide an improved system for latching the cartridge to the instrument.
Further, in order to facilitate attachment of a cartridge to an instrument, it would be beneficial to provide a system that would hold the interior components of the cartridge in position as the attachment connections to the instrument are being made.
In addition, it would be highly desirable to insure that the cartridge is properly installed on the instrument. To this end, it would be desirable to provide a loading or installation tool for assisting in the installation of the cartridge on the instrument in a way that would minimize the likelihood of an incomplete or improper installation.
It would be desirable in some applications to provide a fastener-containing cartridge that could rotate about its axis at the distal end of the instrument so as to facilitate positioning of the fastener in a desired orientation. Preferably, such cartridge rotation should be effected from the handle at the proximal end of the instrument.
While the rotational capability of the cartridge is highly desirable for this purpose, it would also be advantageous to provide means for preventing such rotation at certain times. In particular, it would be beneficial to provide a system for preventing cartridge rotation when external forces or moments are applied to the cartridge, as from contact with surrounding tissue or during installation of the cartridge.
Regardless of whether or not a fastener cartridge rotates at the distal end of an instrument, it would also be desirable in some applications to rotate the entire, elongate endoscopic shaft relative to the proximal handle of the instrument. It would be especially beneficial to provide the capability for effecting such shaft rotation from the proximal, handle portion of the instrument. This would permit orientation of the shaft to a particular rotated position that would be most convenient during a particular surgical procedure. However, once the shaft has been rotated to the selected position, it would be desirable to provide a system for maintaining the selected position. In particular, it would be desirable to provide an improved system for preventing rotation of the shaft when the shaft is subjected to forces and moments from surrounding tissue, or when a cartridge at the end of the shaft is separately rotated.
The present invention provides an improved jaw assembly for an instrument used in a surgical procedure which can accommodate designs having the above-discussed benefits and features.